1 /* $NetBSD: nslu2_iic.c,v 1.12 2021/08/07 16:18:50 thorpej Exp $ */
2
3 /*-
4 * Copyright (c) 2006 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Steve C. Woodford.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/device.h>
36 #include <sys/mutex.h>
37 #include <sys/bus.h>
38
39 #include <dev/i2c/i2cvar.h>
40 #include <dev/i2c/i2c_bitbang.h>
41
42 #include <arm/xscale/ixp425reg.h>
43 #include <arm/xscale/ixp425var.h>
44
45 #include <evbarm/nslu2/nslu2reg.h>
46
47 struct slugiic_softc {
48 struct i2c_controller sc_ic;
49 struct i2c_bitbang_ops sc_ibo;
50 uint32_t sc_dirout;
51 };
52
53 static int
slugiic_send_start(void * arg,int flags)54 slugiic_send_start(void *arg, int flags)
55 {
56 struct slugiic_softc *sc = arg;
57
58 return (i2c_bitbang_send_start(sc, flags, &sc->sc_ibo));
59 }
60
61 static int
slugiic_send_stop(void * arg,int flags)62 slugiic_send_stop(void *arg, int flags)
63 {
64 struct slugiic_softc *sc = arg;
65
66 return (i2c_bitbang_send_stop(sc, flags, &sc->sc_ibo));
67 }
68
69 static int
slugiic_initiate_xfer(void * arg,i2c_addr_t addr,int flags)70 slugiic_initiate_xfer(void *arg, i2c_addr_t addr, int flags)
71 {
72 struct slugiic_softc *sc = arg;
73
74 return (i2c_bitbang_initiate_xfer(sc, addr, flags, &sc->sc_ibo));
75 }
76
77 static int
slugiic_read_byte(void * arg,uint8_t * vp,int flags)78 slugiic_read_byte(void *arg, uint8_t *vp, int flags)
79 {
80 struct slugiic_softc *sc = arg;
81
82 return (i2c_bitbang_read_byte(sc, vp, flags, &sc->sc_ibo));
83 }
84
85 static int
slugiic_write_byte(void * arg,uint8_t v,int flags)86 slugiic_write_byte(void *arg, uint8_t v, int flags)
87 {
88 struct slugiic_softc *sc = arg;
89
90 return (i2c_bitbang_write_byte(sc, v, flags, &sc->sc_ibo));
91 }
92
93 static void
slugiic_set_dir(void * arg,uint32_t bits)94 slugiic_set_dir(void *arg, uint32_t bits)
95 {
96 struct slugiic_softc *sc = arg;
97 uint32_t reg;
98 int s;
99
100 if (sc->sc_dirout == bits)
101 return;
102
103 s = splhigh();
104
105 sc->sc_dirout = bits;
106
107 if (sc->sc_dirout) {
108 /* SDA is output; enable SDA output if SDA OUTR is low */
109 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
110 if ((reg & GPIO_I2C_SDA_BIT) == 0) {
111 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
112 reg &= ~GPIO_I2C_SDA_BIT;
113 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
114 }
115 } else {
116 /* SDA is input; disable SDA output */
117 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
118 reg |= GPIO_I2C_SDA_BIT;
119 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
120 }
121
122 splx(s);
123 }
124
125 static void
slugiic_set_bits(void * arg,uint32_t bits)126 slugiic_set_bits(void *arg, uint32_t bits)
127 {
128 struct slugiic_softc *sc = arg;
129 uint32_t oer, outr;
130 int s;
131
132 s = splhigh();
133
134 /*
135 * Enable SCL output if the SCL line is to be driven low.
136 * Enable SDA output if the SDA line is to be driven low and
137 * SDA direction is output.
138 * Otherwise switch them to input even if directions are output
139 * so that we can emulate open collector output with the pullup
140 * resistors.
141 * If lines are to be set to high, disable OER first then set OUTR.
142 * If lines are to be set to low, set OUTR first then enable OER.
143 */
144 oer = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
145 if ((bits & GPIO_I2C_SCL_BIT) != 0)
146 oer |= GPIO_I2C_SCL_BIT;
147 if ((bits & GPIO_I2C_SDA_BIT) != 0)
148 oer |= GPIO_I2C_SDA_BIT;
149 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer);
150
151 outr = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
152 outr &= ~(GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT);
153 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, outr | bits);
154
155 if ((bits & GPIO_I2C_SCL_BIT) == 0)
156 oer &= ~GPIO_I2C_SCL_BIT;
157 if ((bits & GPIO_I2C_SDA_BIT) == 0 && sc->sc_dirout)
158 oer &= ~GPIO_I2C_SDA_BIT;
159 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, oer);
160
161 splx(s);
162 }
163
164 static uint32_t
slugiic_read_bits(void * arg)165 slugiic_read_bits(void *arg)
166 {
167 uint32_t reg;
168
169 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPINR);
170 return (reg & (GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT));
171 }
172
173 static void
slugiic_deferred_attach(device_t self)174 slugiic_deferred_attach(device_t self)
175 {
176 struct slugiic_softc *sc = device_private(self);
177 struct i2cbus_attach_args iba;
178 uint32_t reg;
179
180 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOUTR);
181 reg |= GPIO_I2C_SDA_BIT | GPIO_I2C_SCL_BIT;
182 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOUTR, reg);
183
184 reg = GPIO_CONF_READ_4(ixp425_softc, IXP425_GPIO_GPOER);
185 reg &= ~GPIO_I2C_SCL_BIT;
186 reg |= GPIO_I2C_SDA_BIT;
187 GPIO_CONF_WRITE_4(ixp425_softc, IXP425_GPIO_GPOER, reg);
188
189 memset(&iba, 0, sizeof(iba));
190 iba.iba_tag = &sc->sc_ic;
191 config_found(self, &iba, iicbus_print, CFARGS_NONE);
192 }
193
194 static int
slugiic_match(device_t parent,cfdata_t cf,void * aux)195 slugiic_match(device_t parent, cfdata_t cf, void *aux)
196 {
197
198 return (1);
199 }
200
201 static void
slugiic_attach(device_t parent,device_t self,void * aux)202 slugiic_attach(device_t parent, device_t self, void *aux)
203 {
204 struct slugiic_softc *sc = device_private(self);
205
206 aprint_naive("\n");
207 aprint_normal(": I2C bus\n");
208
209 iic_tag_init(&sc->sc_ic);
210 sc->sc_ic.ic_cookie = sc;
211 sc->sc_ic.ic_send_start = slugiic_send_start;
212 sc->sc_ic.ic_send_stop = slugiic_send_stop;
213 sc->sc_ic.ic_initiate_xfer = slugiic_initiate_xfer;
214 sc->sc_ic.ic_read_byte = slugiic_read_byte;
215 sc->sc_ic.ic_write_byte = slugiic_write_byte;
216
217 sc->sc_ibo.ibo_set_dir = slugiic_set_dir;
218 sc->sc_ibo.ibo_set_bits = slugiic_set_bits;
219 sc->sc_ibo.ibo_read_bits = slugiic_read_bits;
220 sc->sc_ibo.ibo_bits[I2C_BIT_SDA] = GPIO_I2C_SDA_BIT;
221 sc->sc_ibo.ibo_bits[I2C_BIT_SCL] = GPIO_I2C_SCL_BIT;
222 sc->sc_ibo.ibo_bits[I2C_BIT_OUTPUT] = 1;
223 sc->sc_ibo.ibo_bits[I2C_BIT_INPUT] = 0;
224
225 sc->sc_dirout = 0;
226
227 /*
228 * Defer until ixp425_softc has been initialised
229 */
230 config_interrupts(self, slugiic_deferred_attach);
231 }
232
233 CFATTACH_DECL_NEW(slugiic, sizeof(struct slugiic_softc),
234 slugiic_match, slugiic_attach, NULL, NULL);
235